The present invention relates to a motor vehicle structural component, especially a specialized front wall.
Document EP-370,342-B1 teaches a hybrid structural component comprising a basic body in the form of a shell containing plastic ribs.
These ribs are obtained by injection moulding a plastic, when overmoulding the shell. This plastic passes through perforations in the shell and extends beyond the external face of the said shell, thus definitively fastening the ribs to the shell.
This structural component is complex to produce both because the overmoulding process with projection of material is difficult to implement and because the shell by itself may not have s simple shape.
As a result, the manufacturing cost of such a component is relatively high.
In addition, EP-370,342-B1 does not envisage the case of a structural component having a part serving for receiving functional members, as is the case for a specialized front wall of a motor vehicle, which must especially house the vehicle""s optical systems and, for example, the radiator, a lock and wipers for the optical systems.
The object of the present invention is to provide a structural component of different construction, of which the constitutive parts, and especially those corresponding to the shell of the prior art, are simpler to produce, and which employs a manufacturing process which is also simpler.
The subject of the present invention is a motor vehicle structural component, especially a specialized front wall, comprising a functional part made of moulded plastic intended to support functional members of the vehicle and a structural part intended to withstand the various mechanical stresses generated by the use of the vehicle, this structural part consisting of the combination of two rigid assemblies, namely, in the first place, an array of stiffening ribs and, in the second place, metal reinforcements, the structural component being characterized in that the functional part and one of the rigid assemblies are made as one piece when moulding the plastic functional part, while the other rigid assembly is attached to the first rigid assembly to which it is fixed by snap-fastening.
The structural component according to the invention is thus produced in two steps.
Firstly, its functional part and one of the rigid assemblies are formed and then, secondly, the other rigid assembly is joined to the first.
In a first embodiment of the invention, the metal reinforcements are overmoulded when moulding the functional part, and then the array of ribs is snapped into the metal reinforcements.
According to a first version of this embodiment, the metal reinforcements include at least one overmoulded clip produced when moulding the functional part, this clip being used for snap-fastening the array of ribs.
According to another version, the array of ribs includes shaped snap-fastening pieces capable of being snapped onto panels with flanged edges of the metal reinforcements.
In a second embodiment of the invention, the array of ribs and the functional part are produced simultaneously by moulding a plastic, and the metal reinforcements are snapped onto the array of ribs.
According to a first version of this embodiment, the metal reinforcement includes at least one hole into which a shaped catching piece, produced in the array of ribs, penetrates.
The elasticity needed for the snap-fastening may result from the shaped catching piece integral with the array of ribs or from the edges of the hole in the metal reinforcement.
In a preferred version, the catching piece protudes from the intersection of two ribs of the array of ribs. Shrink marks may then be avoided on the side of the rigid assembly opposite the metal reinforcement, said side thus being able to constitute a visible skin, and possibly a painted piece.
In order to limit the bulkiness of the catching piece protruding from the intersection of the ribs, said catching piece may be shaped as a cross whose legs are strictly comprised in the thickness of the ribs. Thus, the catching piece shows an overall diameter broader than the thickness of the ribs but does not thicken said ribs in the area of their intersection.